JPS63176141A - Manufacture of polyimide tubular material - Google Patents

Abstract

PURPOSE:To easily facilitate manufacturing of various seamless tubular materials which has neither a stuck part nor a difference in level on the surface and maintains excellent heat resisting property possessed by polyimide, by a method wherein a polyamide acid solution is applied onto an inner circumferential surface of a cylinder and a tubular material is formed by heating the same. CONSTITUTION:A polyamide acid solution is applied onto an inner circumferential surface of a cylinder by extruding the same through a round die, then a solvent within the foregoing solution is removed and imide conversion of the polyamide acid is performed. Then a polyimide tubular material is formed on the inner circumferential surface of the cylinder, and then the tubular material is peeled off from the cylinder. The polyamide acid solution can be obtained by reacting, for example, an aromatic tetracarboxylic acid 2 unhydride (or its derivative) and about an equimolar material of aromatic diamine an organic polar solvent. The polyamide tubular material formed by making use of the polyamide acid solution of intrinsic viscosity of 0.5 or higher is especially superior in properties resisting to heat deterioration.

Description

[Detailed description of the invention] (Field of application with pressure work) The present invention relates to a novel method for manufacturing polyimide tubular articles.

(Prior Art) Polyimide has excellent heat resistance, mechanical properties, and chemical properties, and tubular products thereof are expected to have various uses.

Examples of applications of polyimide tubular materials include power transmission belts with relatively small transmission force, such as endless belts for thermal transfer printers, and belts for transporting paper in office equipment (e.g., office automation equipment).

By the way, as a method for producing such polyimide tubular products, a method is known in which polyimide tape is wound around a mandrel in a spiral or sushi-wound shape, the overlapping parts of the tapes are adhered with an adhesive, and the tape is pulled out from the mandrel. .

(Problems to be Solved by the Invention) However, the tubular product obtained by this method must be used at a temperature below the heat resistance temperature of the adhesive, and there is a problem that the excellent heat resistance of polyimide cannot be fully utilized. Furthermore,
This tubular object has a step at the adhesive part, and when it is installed in a thermal transfer printer for printing, the shading of the characters printed on the recording paper may differ between the first step and the other parts, and the clarity may be different. This may cause some inconveniences such as unevenness.

Accordingly, one object of the present invention is to provide a polyimide tubular product that does not have adhesive portions or steps and can fully exhibit the excellent heat resistance of polyimide.

(Means for Solving the Problems) A novel method for manufacturing polyimide tubular products according to the present invention involves extruding a polyimide acid solution from a circular die and applying it to the inner peripheral surface of a cylinder, and then removing the solvent in the solution. , and is characterized by converting polyamic acid into imide to form a polyimide tubular material on the inner circumferential surface of the cylinder, and then peeling the tubular material from the cylinder.

In the present invention, first, a heat-resistant cylinder (cylindrical body) made of metal, glass, ceramic, fluororesin, etc. and having an inner diameter of about 1 to 50 mm is usually coated with silicone resin, fluororesin, etc. on the inner circumferential surface. A polyamic acid solution is applied to the inner circumferential surface of the material (Wi type treatment is applied by coating).

The polyamic acid solution can be applied to the inner peripheral surface of the cylinder by disposing a round die in the cylinder and extruding the polyamic acid solution from the die while moving at least one of the cylinder and the die. During this coating, the cylinder is held vertically, horizontally, or inclined, but it can also be rotated to make the coating thickness uniform. Further, the coating thickness of the polyamic acid solution can be adjusted mainly by the lip gap of the round die, the coating speed (running speed of the die or cylinder), and the amount of the polyamic acid solution discharged from the die.

The poly-1-mide acid solution used in the present invention can be obtained, for example, by reacting approximately equal moles of aromatic tetracarboxylic dianhydride (or its derivative) and aromatic diamine in an organic polar solvent.

Specific examples of the aromatic tetracarboxylic dianhydride include pyromellitic dianhydride; 3. 3', 4. 4'
-benzophenonetetracarboxylic acid 2 m hydrate, 3°3
', 4. 4'-biphenyltetracarboxylic dianhydride, 2. 3. 3', 4'-biphenyltetracarboxylic dianhydride, 2,3y 6t 7-naphthalenetetracarboxylic dianhydride, 1. 2. 5.
6-naphthalenetetracarboxylic dianhydride, 1,4,5
．． 8-naphthalenetetracarboxylic dianhydride, 2,2'
-bis(3,4-dicarboxyphenyl)furopane 2f
Examples thereof include R hydrate, bis(3,4-dicarboxyphenyl)sulfone dianhydride, and the like.

Further, specific examples of aromatic diamines include 4゜4'-
Diaminodiphenyl ether, 4.4'-diaminodiphenylmethane, 3.3'-diaminodiphenylmethane,
Paraphenylenediamine, metaphenylenediamine, benzidine, 3,3'-dimethylpentedine, 3,3'-
Dimethoxybenzidine, 4゜4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfide,
Examples include 4'-diaminodiphenylpropane, 2,2-bis(4-(4aminophenoxy)phenyl)furopane, and the like.

Furthermore, as a specific example of the organic polar solvent, N-methyl-2
-Pyrrolidone, dimethylacetamide, dimethylformamide, dimethylsulfoxide, hexamethylenephosphortriamide, and the like. Phenols such as cresol, phenol, xylenol, hexane, Hensen, toluene, etc. can also be mixed with these organic polar solvents.

The monomer concentration when reacting aromatic tetracarboxylic dianhydride and aromatic diamine in a solvent to obtain polyamic acid can be set depending on various conditions, but is usually 5 to 1.
It is 40% by weight. '1 thought.

The reaction temperature is usually 80°C or less, preferably 5 to 50°C, and the reaction time is usually about 2 to 10 hours.

When aromatic tetracarboxylic dianhydride and aromatic diamine are reacted in an organic polar solvent in this way, polyamic acid is produced, and the solution viscosity increases as the reaction progresses. It is preferable to obtain a polyamic acid solution having an intrinsic viscosity of 0.5 or more. A polyimide tubular article formed using a polyamic acid solution having an intrinsic viscosity of 0.5 or more is characterized by particularly excellent resistance to thermal deterioration.

The intrinsic viscosity of the polyamic acid solution is the value calculated by the following formula (1) after removing the polyamic acid from the polyamic acid solution, dissolving this polyamic acid in a specified solvent, and measuring the solution viscosity. =□・・・(l
C in the above formula (1) represents the number of grams of polyamic acid in 100 at of solution.

When the polyamic acid solution obtained in this manner is used in the present invention, if the viscosity thereof is high, it can be diluted with an appropriate Fi solvent to lower the viscosity.

The viscosity of the polyamic acid solution when applied to the inner peripheral surface of the cylinder can be set depending on the coating thickness, the inner diameter of the cylinder, the temperature of the solution, the amount of discharge from the die, the coating speed, etc., but is usually about 10 ~l 0000 poise (temperature when working with ik cloth, measured value with a B-type viscometer). The concentration of polyamic acid in the polyamic acid solution is usually about 5 to 40% by weight, preferably 10 to 30% by weight.

After applying the polyamic acid solution to the inner peripheral surface of the cylinder in this manner, heating is performed. This heating is performed in order to remove the solvent in the solution and convert the polyamic acid into imide. In order to prevent the formation of voids due to evaporation of the solvent and evaporation of ring-closing water etc. generated by WCVc of imide conversion,
The solvent is removed by heating at a temperature of about 80 to 180'C for about 20 to 60 minutes, and then the solvent is heated at a temperature of about 250 to 350'C for about 20 to 60 minutes to evaporate ring-closing water, etc. and convert the imide. It is preferable to adopt a method in which the

Due to such heating, a polyimide tubular material is formed on the inner circumferential surface of the cylinder, and the tubular material is peeled from the cylinder. This tubular material can be used as it is or by cutting it into a predetermined length. Also, if you use the method of the present invention! 1
A tubular article having dimensions a and a is obtained, but typically has an outer circumference of about 50-15QOii and a wall thickness of about 10-150 Atm.

The polyimide tubular product obtained by the method of the present invention as described above is seamless, and there is no step difference in the adhesive part on the surface of the tubular product, and it can be used not only for thermal transfer printers, but also for conveyance or fixing belts in copying machines, and for conveyance of silicon wafers. It can be used for a variety of purposes, such as belts for industrial use, laminated fusing belts for thermoplastic belts, etc.

(Example) Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 Equimolar amounts of 3.3,4.4'-biphenyltetracarboxylic acid 2M hydrate and 4.4'-diaminodiphenyl ether were placed in N-methyl-2-pyrrolidone (monomer concentration 20% by weight solution) at temperature React at 20°C for 5 hours to obtain a viscosity of 35,000 boids (measured at 50°C with a B-type viscometer).
A polyamic acid solution with an intrinsic viscosity of 2.8 is obtained.

This polyamic acid solution was heated at 50° C. for 24 hours to give a viscosity of 3000 poise) and an inner diameter of zoomyt.

Apply to the inner peripheral surface of a stainless steel cylinder with an outer diameter of 230 mg and a length of 500 yat. For coating, place a round die inside the cylinder and pour polyamic acid solution 1140 from the die.
Discharge at a rate of g/min and move the cylinder to 0.5 m.
The test was carried out by running at a speed of /min. The cylinder used had an inner circumferential surface finished with IS, and this surface was coated with silicone resin and subjected to mold release treatment. In addition, through holes were provided in the wall near the openings at both ends of this cylinder, and the through holes were closed with plugs for use.

Next, this was heated at 150°C for 60 minutes and at 300°C for 60 minutes.
The cylinder is heated for several minutes to remove the solvent, ring-closing water, etc., and perform imide conversion to form a polyimide tube on the inner peripheral surface of the cylinder, and then cooled to room temperature.

Thereafter, the openings at both ends of the cylinder are closed, and the plug blocking the cylinder through-hole is removed. Then,
Air was forced through the through hole to peel the polyimide tubular object from the inner peripheral surface of the cylinder, and the tubular object was pulled out.

This polyimide tubing is seamless and has an outer circumference of 62 mm.
It was 8B, wall thickness 50 μfi, and length 450 mttr.

Then, the above operations were repeated to obtain 100 polyimide seamless tubular products. The variation in the outer circumferential length of these tubular bodies was 0.01% or less, and the dimensional accuracy was high.

Example 2 Equal moles of pyromellitic dianhydride and 4,4'-diaminodiphenyl ether were mixed in N-methyl-2-pyrrolidone (
A monomer concentration of 20% by weight solution) was reacted at a temperature of 10°C for 10 hours to achieve a viscosity of 25,000 poise (50°C, B
A polyamic acid solution with an intrinsic viscosity of 2.4 (measured with a type viscometer) is obtained.

Example 1 except that this polyamic acid solution was heated at 50° C. for 24 hours (the viscosity became 2500 poise) and the running speed of the stainless steel cylinder was set to 37 m/min.
Worked in the same manner as above, and the outer circumference length was 628 mff.

A polyimide seamless tubular product having a length of 450 ηm was obtained by rinsing 11qi75μ.

This operation was repeated to obtain 1()0 seamless tubular products. The variation in the outer circumferential length of these tubular objects was 0.01% or less, and the two-dimensional accuracy was high.

(Effects of the Invention) The present invention is constructed as described below, in which a polyamic acid solution is applied to the inner circumferential surface of the cylinder and heated to form a tubular body, so that one surface has adhesive parts and It is possible to easily obtain a seamless polyimide tubular body that has no steps and maintains the excellent heat resistance of polyimide, and can also be made from small to large diameter tubular bodies, or from thin to thick wall 1, depending on the inner diameter of the cylinder. It is characterized by the ability to freely manufacture tubular bodies.

Claims (1)

[Claims] A polyamic acid solution is extruded from a circular die and applied to the inner peripheral surface of the cylinder, then the solvent in the solution is removed, and the polyamic acid is converted into an imide to form a polyimide tube on the inner surface of the cylinder, and then the tube is extruded from the cylinder. A method for producing a polyimide tubular article, which is characterized by peeling the article.